This invention relates to pinned opening rollers or beaters for open end spinning machines wherein a sliver or untwisted rope of fibres is separated by the opening or combing roller or beater into individual fibres, which are assembled into a yarn. Such an opening roller carries an array of sharp projections which may either be in the form of saw-toothed wire wound helically onto the circumferential surface of the roller or of individual pins projecting from the said surface of the roller.
Conventionally two types of pin pattern have been used for the pinned type of roller with the basic difference that in one type the distance from pin to pin within a row is approximately equal to the distance between the rows (equal relationship) while in the other pattern (unequal relationship) a similar number of pins are disposed in each roller, but there are fewer rows with more pins in each row, than is the case with the equal relationship.
Both these alternative type of roller can be used, one type being more suited to some designs of open end spinning machines and the other for other designs of machine.
In order to provide a sufficiently intensive opening action on the fibres, the distance from pin to pin in each row in the case of the opening roller with unequal relationship has to be relatively close. This in turn limits the diameter of the pin which can be utilised as sufficient roller material has to be left for the matrix holding the pins not to be unduly weakened. Furthermore, the reduced diameter of the pins means they are weaker and also wear more quickly.